Metallic articles to be heat-treated are most commonly adhered or impregnated with machine oils or powder metallurgical waxes which are unnecessary and obstructive for heat-treatments for their carburization, sintering and so on. Such oils and waxes must be removed before the articles are subjected to the heat-treatments.
This invention relates to a method for removing from articles to be heat-treated, before they are heat-treated, combustibles such as above-mentioned unnecessary and obstructive oily substances, and also to an apparatus therefor.
There is described in Japanese Preliminary Patent Publication No.Hei-9-170091 a method of removal by evaporation of oily substances from metallic articles, in which the articles are heated in a heating chamber for evaporating the oily substances adhered to the articles, evaporated oily substances are led with a heating atmosphere to the outside of the chamber, they are separated at the outside to the oily substances and the heating atmosphere, and the substances and atmosphere thus separated are resent to the heating chamber where the oily substances are utilized as a heating source of burners in the chamber, and the atmosphere is reused as a heating atmosphere of the chamber.
Although this prior method contributes to the saving of fuel and so on, and is also favorable in an environmental protection, since it does not employ harmful organic solvents such as trichloroethylene, the method and an apparatus for achieving it are not so simple.
It is therefore, an object of this invention to provide a method for removing from articles to be heat-treated, before they are subjected to a heat-treatment, oily combustibles which are unnecessary and obstructive to the heat-treatment, without employing harmful organic solvents on account of an environmental protection and in a simple manner than the method taught by the above-mentioned Japanese Preliminary Patent Publication.